The present invention relates to antiperspirant compositions for administration as an aerosol to human skin. More particularly, it relates to such aerosol compositions with improved cosmetic characteristics.
Compositions designed to stop or reduce the flow of human perspiration are well known in the chemical and cosmetic literature. Such antiperspirant compositions may be applied to the skin by a variety of methods. For example, S. Plechner, "Antiperspirants and Deodorants" 2 Cosmetics, Science and Technology, 373-416 (M. Balsam and E. Sagarin ed. 1972), describes antiperspirant compoitions in spray, roll-on, cream and stick forms. Depending upon such factors as the method of application, the intended use, and the desired rheology, such compositions may contain a variety of different vehicle materials in addition to an astringent antiperspirant active.
For a variety of reasons, one method of application that has gained wide consumer acceptance is the aerosol form. Such compositions typically are anhydrous systems comprising an antiperspirant salt dispersed in a liquid vehicle together with a liquified volatile propellant in a pressurized aerosol container. The aerosol spray is created, then, by the rapid boiling of the propellant upon dispensing from an atomizing valve. Such aerosol containers are described, for example, in U.S. Pat. No. 3,083,917 and U.S. Pat. No. 3,083,918, Abplanalp, et al., issued Apr. 2, 1963, and U.S. Pat. No. 3,544,258, Presant, et al., issued Dec. 1, 1970.
Antiperspirant aerosol compositions present, however, several cosmetic problems. For example, such compositions may create a cooling sensation when applied to the skin, or they may be very dusty or powdery once applied. such compositions may also create excessive dustiness or mistiness during application. Also, such compositions may require excessive shaking or agitation prior to, and during, use in order to maintain adequate suspension or dispersion of the active material in the product. Failure to maintain such active or product suspension may lead (for example) to dispensing of propellant or other vehicle materials with little or no antiperspirant active. This problem may be particularly significant with respect by compositions containing high molecular weight silicone gums, as disclosed in U.S. Pat. No. 4,152,416, Spitzer, et al., issued May 1, 1979.
It has now been discovered that aerosol antiperspirant compositions containing certain functionalized siloxanes have improved application, cosmetic and performance characteristics than compositions known in the art. For example, the aerosol antiperspirants of this invention have improved adherence to the skin, and improved product suspension and redispersibility (i.e., maintaining more extensive suspension or dispersion of active materials in the product, with lower rates of settling), as well as other improved cosmetic characteristics.